1. Field of the Invention
The present invention relates to a paper roll driving apparatus. More particularly, in a web feeder of a rotary press using a paper roll, the present invention relates to a paper roll driving apparatus for rotating and driving a next paper roll when a paper roll is spliced with a next paper roll.
2. Description of the Prior Art
During splicing in a web feeder of a rotary press using a paper roll, it is generally necessary that the travelling speed of a travelling web paper pulled out in advance from a paper roll be equal to the peripheral speed of a next paper roll. Therefore, a paper roll driving apparatus for rotating and driving a next paper roll is disposed in the web feeder.
Paper roll driving apparatus of this kind are known from "Pre-Drive" in "Newspaper Printing, Printing Edition, Revised Edition", pp. 74-75, (issued on Oct. 31, 1980, by Japan Newspaper Association, Foundation), Japanese Utility Model Publication No. 19602/1958, Japanese Utility Model Laid-Open No. 73002/1973, Japanese Patent Publication No. 48785/1988 and Japanese Utility Model Publication No. 8920/1990.
In the prior art apparatuses disclosed in "Newspaper Printing, Printing Edition, Revised Edition" (issued on Oct. 31, 1980, by Japan Newspaper Association, Foundation), pp. 74-75 and in Japanese Utility Model Publication No. 19602/1958, a driving endless belt or a driving wheel which can come into contact with, and can come out contact from, the outer peripheral surface of a next paper roll and is interconnected to driving means is brought into pressure contact with the outer peripheral surface of the next paper roll and is rotated under such a state, so that the paper roll is driven directly for rotation.
In the apparatus disclosed in Japanese Utility Model Laid-Open No. 73002/1973, a friction wheel is disposed on the support shaft of a paper roll and a driving roller or driving belt which can come into pressure contact with the friction wheel and is interconnected to driving means is brought into pressure contact with the friction wheel disposed on the support shaft to the paper roll and is driven for rotation under such a state, so that the paper roll is driven and rotated through the support shaft.
In the apparatus disclosed in Japanese Patent Publication No. 48785/1988 and Japanese Utility Model Publication No. 8920/1990, a gear is disposed on the support shaft of a paper roll and a driving gear is further disposed which can mesh with the gear and is interconnected to driving means. The driving gear is driven and rotated while it is engaged with the gear disposed on the support shaft of the paper roll and the paper roll is driven and rotated through the support shaft.
Each of the prior art apparatuses described above is not free from the following drawbacks.
In the apparatuses of "Newspaper Printing, Printing Edition, Revised Edition" (issued on Oct. 31, 1980, by Japan Newspaper Association, Foundation), pp. 74-75 and in Japanese Utility Model Publication No. 19602/1988, the driving endless belt or driving wheel is pushed to the outer peripheral surface of the paper roll. Therefore, it is not possible to apply an adhesive for splicing to that end of paper roll corresponding to the pushed portion and bonding power at the time of splicing drops. Since slip occurs between the driving endless belt or driving wheel and the outer peripheral surface of the paper roll, a stable peripheral speed of the paper roll cannot be obtained and the outer peripheral surface of the paper roll might be damaged.
In the apparatus disclosed in Japanese Utility Model No. 73002/1973, slip occurs between the friction wheel and the driving roller or driving belt and a stable peripheral speed of the paper roll cannot be obtained. The friction wheel, the driving roller and the driving belt are worn out during their use for a long period and transmission of the driving force at a set peripheral speed cannot be made.
In the apparatuses disclosed in Japanese Patent Publication No. 48785/1988 and Japanese Utility Model Publication No. 8920/1990, the center distance must be kept accurate when the gear disposed on the support shaft of the paper roll and the driving gear are engaged with each other. Therefore, a special gear equipped with a cylindrical portion becomes necessary and the cost of the apparatus becomes high. Furthermore, this cylindrical portion is worn out in the course of its use for a long period, so that the set center distance cannot be maintained and the gears might be damaged. The rotation of the gears while they are engaged generates noise and deteriorates working environments.